disable password checking against ldap

[Kong Kai Chen]

In steel belted radius (SBR), we can setup sbr to do a simple bind to ldap database. 
In such as setup, sbr will omit password checking. If the bind is successful (meaning username is found in ldap) then reply accept being sent back to radius client.
When I try to do this in freeradius, it passes the authentication process to ldap and insists on checking the password. 
How can I disable the password checking in freeRadius?